Trans cyclopentanyl purine analogs useful as immunosuppressants

ABSTRACT

This invention relates to Trans cyclopentanyl purine analogs of the formula (1) ##STR1## wherein the substituent in the 3-position on the cyclopentanyl ring is in the Trans configuration relative to the bicyclic substituent, 
     Y 3 , Y 5  and Y 9  are each nitrogen and Y 7  and Y 8  are a CH group, 
     R is a C 1  -C 7  alkyl acyl or aryl acyl, 
     Q is NH 2 , halogen or hydrogen, 
     Z is hydrogen, halogen, or NH 2  ; 
     or a pharmaceutically-acceptable salt thereof, and to their use as immunosuppressants.

This application is a continuation-in-part of application Ser. No.08/369,576, filed Jan. 6, 1995, now abandoned, which is a continuationof application Ser. No. 07/965,601, filed Nov. 2, 1992, now abandoned,which is a continuation-in-part of application Ser. No. 07/804,153,filed Dec. 6, 1991, now abandoned.

FIELD OF THE INVENTION

This invention relates to certain Trans cyclopentanyl purine analogswhich are useful as immunosuppressants.

BACKGROUND OF THE INVENTION

Immunity is concerned with the recognition and disposal of foreignantigenic material which is present in the body. Typically the antigensare in the form of particulate matter (i.e., cells, bacteria, etc.) orlarge protein or polysaccharide molecules which are recognized by theimmune system as being "non-self", i.e., detectably different or foreignfrom the animals own constituents. Potential antigens can be a varietyof substances, often proteins, which are most frequently located on theouter surfaces of cells. For example, potential antigens can be found onpollen grains, tissue grafts, animal parasites, viruses, and bacteria.Once the antigenic material is recognized as "non-self" by the immunesystem, natural (non-specific) and/or adaptive immune responses can beinitiated and maintained by the action of specific immune cells,antibodies and the complement system. Under certain conditions,including in certain disease states, an animal's immune system willrecognize its own constituents as "non-self" and initiate an immuneresponse against "self" material.

An immune response can be carried out by the immune system by means ofnatural or adaptive mechanisms, each of which are composed of bothcell-mediated and humoral elements. Natural mechanisms for immuneresponse refer to those mechanisms involved in essentially non-specificimmune reactions which involve the complement system and myeloid cellsalone, such as macrophages, mast cells and polymorphonuclear leukocytes(PMN), in reacting to certain bacteria, viruses, tissue damage and otherantigens. These natural mechanisms provide what is referred to asnatural immunity. Adaptive mechanisms for immune response refer to thosemechanisms which are mediated by lymphocytes (T and B cells) andantibodies which can respond selectively to thousands of differentmaterials recognized as "non-self". These adaptive mechanisms providewhat is referred to as adaptive immunity and lead to a specific memoryand a permanently altered pattern of response in adaptation to theanimal's own environment. Adaptive immunity can be provided by thelymphocytes and antibodies alone or, more commonly, can be provided bythe interaction of lymphocytes and antibodies with the complement systemand myeloid cells of the natural mechanisms of immunity. The antibodiesprovide the humoral element of the adaptive immune response and theT-cells provide the cell-mediated element of the adaptive immuneresponse.

Natural mechanisms of immune response involve phagocytosis bymacrophages and PMN whereby foreign material or antigen is engulfed anddisposed of by these cells. In addition, macrophages can kill someforeign cells through its cytotoxic effects. The complement system whichis also involved in natural immunity is made up of various peptides andenzymes which can attach to foreign material or antigen and therebypromote phagocytosis by macrophages and PMN, or enable cell lysis orinflammatory effects to take place.

Adaptive mechanisms of immune response involve the actions againstspecific antigens of antibody secreted by B-lymphocytes (or B-cells) aswell as the actions of various T-lymphocytes (or T-cells) on a specificantigen, on B-cells, on other T-cells and on macrophages.

Antibodies, which are responsible for the humoral aspect of adaptiveimmunity, are serum globulins secreted by B-cells with a wide range ofspecificity for different antigens. Antibodies are secreted in responseto the recognition of specific antigens and provide a variety ofprotective responses. Antibodies can bind to and neutralize bacterialtoxins and can bind to the surface of viruses, bacteria, or other cellsrecognized as "non-self" and thus promote phagocytosis by PMN andmacrophages. In addition, antibodies can activate the complement systemwhich further augments the immune response against the specific antigen.

Lymphocytes are small cells found in the blood which circulate from theblood, through the tissues, and back to the blood via the lymph system.There are two major subpopulations of lymphocytes called B-cells andT-cells. B-cells and T-cells are both derived from the same lymphoidstem cell with the B-cells differentiating in the bone marrow and theT-cells differentiating in the thymus. The lymphocytes possess certainrestricted receptors which permit each cell to respond to a specificantigen. This provides the basis for the specificity of the adaptiveimmune response. In addition, lymphocytes have a relatively longlifespan and have the ability to proliferate clonally upon receiving theproper signal. This property provides the basis for the memory aspect ofthe adaptive immune response.

B-cells are the lymphocytes responsible for the humoral aspect ofadaptive immunity. In response to recognition of a specific foreignantigen, a B-cell will secrete a specific antibody which binds to thatspecific antigen. The antibody neutralizes the antigen, in the case oftoxins, or promotes phagocytosis, in the case of other antigens.Antibodies also are involved in the activation of the complement systemwhich further escalates the immune response toward the invading antigen.

T-cells are the lymphocytes responsible for the cell-mediated aspect ofadaptive immunity. There are three major types of T-cells, i.e., theCytotoxic T-cells, Helper T-cells and the Suppressor T-cells. TheCytotoxic T-cells detects and destroys cells infected with a specificvirus antigen. Helper T-cells have a variety of regulatory functions.Helper T-cells, upon identification of a specific antigen, can promoteor enhance an antibody response to the antigen by the appropriate B-celland it can promote or enhance phagocytosis of the antigen bymacrophages. Suppressor T-cells have the effect of suppressing an immuneresponse directed toward a particular antigen.

The cell-mediated immune response is controlled and monitored by theT-cells through a variety of regulatory messenger compounds secreted bythe myeloid cells and the lymphocyte cells. Through the secretion ofthese regulatory messenger compounds, the T-cells can regulate theproliferation and activation of other immune cells such as B-cells,macrophages, PMN and other T-cells. For example, upon binding a foreignantigen, a macrophage or other antigen presenting cell can secreteinterleukin-1 (IL-1) which activates the Helper T-cells. T-cells in turnsecrete certain lymphokines, including interleukin-2 (IL-2) andγ-interferon, each of which have a variety of regulatory effects in thecell-mediated immune response. Lymphokines are a large family ofmolecules produced by T-cells (and sometimes B-cells) including

IL-2, which promotes the clonal proliferation of T-cells;

MAF or macrophage activation factor, which increases many macrophagefunctions including phagocytosis, intracellular killing and secretion ofvarious cytotoxic factors;

NAF or neutrophil activation factor, which increases many functions ofthe PMN including phagocytosis, oxygen radical production, bacterialkilling, enhanced chemotaxis and enhanced cytokine production;

MIF or macrophage migration factor, which by restricting the movement ofmacrophages, concentrates them in the vicinity of the T-cell;

γ-interferon, which is produced by the activated T-cell and is capableof producing a wide range of effects on many cells including inhibitionof virus replication, induction of expression of class IIhistocompatibility molecules allowing these cells to become active inantigen binding and presentation, activation of macrophages, inhibitionof cell growth, induction of differentiation of a number of myeloid celllines.

Activated macrophages and PMNs, which provide an enhanced immuneresponse as part of the cell-mediated adaptive immunity, arecharacterized as having increased production of reactive oxygenintermediates. This increased production of reactive oxygenintermediates, or respiratory burst, is known as "priming". Certainlymphokines, such as γ-interferon, trigger this respiratory burst ofreactive oxygen intermediates in macrophages and PMNs. Thus,lymphokines, such as γ-interferon, which are secreted by the T-cellsprovide an activation of these macrophages and PMNs which results in anenhanced cell-mediated immune response.

The immune response can provide an immediate or a delayed type ofresponse. Delayed-type hypersensitivity is an inflammatory reactionwhich occurs in immune reactive patients within 24-48 hours afterchallenge with antigen and is the result primarily of a cell-mediatedimmune response. In contrast, immediate-type hypersensitivity, such asthat seen in anaphylactic or Arthus reactions, is an inflammatoryreaction which occurs in immune reactive patients within minutes to afew hours after challenge with antigen and is the result primarily ofhumoral or antibody-mediated immune response.

The ability of the immune system, and in particular the cell-mediatedimmune system, to discriminate between "self" and "non-self" antigens isvital to the functioning of the immune system as a specific defenseagainst invading microorganisms. "Non-self" antigens are those antigensor substances in the body which are detectably different or foreign fromthe animals own constituents. "Self" antigens are those antigens whichare not detectably different or foreign from the animals ownconstituents. Although the immune response is a major defense againstforeign substances which can cause disease, it cannot distinguishbetween helpful and harmful foreign substances and destroys both.

There are certain situations, such as with an allogeneic transplant orin "graft versus host" disease, where it would be extremely useful tosuppress the immune response in order to prevent the rejection ofhelpful foreign tissue or organs. Allogeneic tissues and organs aretissues and organs from a genetically different member of the samespecies. "Graft versus host" disease occurs where the transplantedtissue, for example in a bone marrow transplant, contains allogeneicT-cells of the donor which cause an immune response against therecipient's own tissues. Although both humoral and cell-mediated immuneresponses play a role in the rejection of allogeneic tissues and organs,the primary mechanism involved is the cell-mediated immune response.Suppression of the immune response, and in particular, suppression ofcell-mediated immune response, would thus be useful in preventing suchrejection of allograft tissues and organs. For example, cyclosporin A iscurrently used as an immunosuppressive agent in the treatment ofpatients receiving allogeneic transplants and in "graft versus host"disease.

There are times when the individual's immunological response causes moredamage or discomfort than the invading microbes or foreign material, asin the case of allergic reactions. Suppression of the immune response inthese cases would be desirable.

Occasionally, the immunological mechanisms become sensitized to somepart of the individual's own body causing interference with or evendestruction of that part. The ability to distinguish between "self" and"not self" is impaired and the body begins to destroy itself. This canresult in an autoimmune diseases such as rheumatoid arthritis,insulin-dependent diabetes mellitus (which involves the autoimmunedestruction of the β-cells of the islets of Langerhans which areresponsible for the secretion of insulin), certain hemolytic anemias,rheumatic fever, thyroiditis, ulceractive colitis, myestheniagravis,glomerulonephritis, allergic encephalo-myelitis, continuing nerve andliver destruction which sometimes follows viral hepatitis, multiplesclerosis and systemic lupus erythematosus. Some forms of autoimmunitycome about as the result of trauma to an area usually not exposed tolymphocytes such as neural tissue or the lens of the eye. When thetissues in these areas become exposed to lymphocytes, their surfaceproteins can act as antigens and trigger the production of antibodiesand cellular immune responses which then begin to destroy those tissues.Other autoimmune diseases develop after exposure of the individual toantigens which are antigenically similar to, that is cross-react with,the individual's own tissue. Rheumatic fever is an example of this typeof disease in which the antigen of the streptococcal bacterium whichcauses rheumatic fever is cross-reactive with parts of the human heart.The antibodies cannot differentiate between the bacterial antigens andthe heart muscle antigens and cells with either of those antigens can bedestroyed. Suppression of the immune system in these autoimmune diseaseswould be useful in minimizing or eliminating the effects of the disease.Certain of these autoimmune diseases, for example, insulin-dependentdiabetes mellitus, multiple sclerosis and rheumatoid arthritis, arecharacterized as being the result of a cell-mediated autoimmune responseand appear to be due to the action of T-cells See Sinha et al. Science248, 1380 (1990)!. Others, such as myestheniagravis and systemic lupuserythematosus, are characterized as being the result of a humoralautoimmune response Id.!.

Suppression of the immune response would thus be useful in the treatmentof patients suffering from autoimmune diseases. More particularly,suppression of cell-mediated immune response would thus be useful in thetreatment of patients suffering from autoimmune diseases due to theaction of T-cells such as insulin-dependent diabetes mellitus, multiplesclerosis and rheumatoid arthritis. Suppression of humoral immuneresponse would be useful in the treatment of patients suffering fromT-cell independent autoimmune diseases such as myestheniagravis andsystemic lupus erythematosus.

SUMMARY OF THE INVENTION

The present invention provides novel compounds of the formula (1)##STR2## wherein the substituent in the three position on thecyclopentanyl ring is in the TRANS configuration relative to thebicyclic substituent,

Y₃, Y₅, Y₇, Y₈ and Y₉ are each independently nitrogen or a CH group,

R is hydrogen, C₁ -C₇ alky acyl or aryl acyl,

Q is NH₂, halogen or hydrogen, and

Z is hydrogen, halogen, or NH₂ ;

or a pharmaceutically-acceptable salt thereof.

The present invention also provides a method of effectingimmunosuppression, and more specifically, a method of suppressingadaptive immunity, in a patient in need thereof comprising administeringto said patient an effective immunosuppressive amount of a compound offormula (1).

In addition, the present invention provides a pharmaceutical compositioncomprising an effective immunosuppressive amount of a compound offormula (1) in admixture or otherwise in association with one or morepharmaceutically acceptable carriers or excipients.

DETAILED DESCRIPTION OF THE INVENTION

As used herein the term "halogen" refers to monovalent iodine, bromine,chlorine or fluorine radicals, the term "nitrogen" refers to a trivalentnitrogen radical and the term "CH group" refers to a methylidyneradical.

As used herein, the term C₁ -C₇ alkyl acyl is composed of an acylsubstituent combined with a C₁ -C₇ alkyl substituent. The term acylrefers to a radical of a carboxylic acid created by the removal of thehydroxide from the carboxy group --C(O)--!. The term C₁ -C₇ alkyl refersto the hydrocarbon radical which may be derived from an alkane havingfrom 1 to 7 carbon atoms in a straight chain or branched chainconfiguration. The combination of a C₁ -C₇ alkyl radical with the acylradical results in the C₁ -C₇ alkyl acyl term. Included within the scopeof the term C₁ -C₇ alkyl acyl are the methyl acyl CH₃ --C(O)--, ethylacyl CH₃ CH₂ --C(O)--, n-propyl acyl CH₃ CH₂ CH₂ --C(O)--, isopropylacyl (CH₃)₂ CH--C(O)--, n-butyl acly CH₃ (CH₂)--C(O)₋₋, sec. butyl acylCH₃ (CH₂)₅ --C(O)--, n-octyl acyl CH₃ (CH₂)₉ --C(O)--, and the like.

The aryl acyl term refers to the radical composed of an acyl substituentand an aryl substituent. The term acyl refers to a radical of acarboxylic acid created by the removal of a hydroxide ion from thecarboxyl group C(O)--!. The term aryl refers to the group that remainsafter the conceptual removal of a hydrogen from a ring position of abenzene or a substituted benzene nucleus. The benzene nucleus may beoptionally substituted with up to three substituents selected from thegroups consisting of Cl, Br, F, I, C₁ -C₄ alkyl, NH₂, or OH. Includedwithin the scope of this term are benzoyl C₆ H₅ --C(O)--,p-chlorobenzoyl C₆ H₄ Cl--C(O)--, 4-fluorobenzoyl C₆ H₄ F--C(O)--,o-toluyl CH₃ C₆ H₄ --C(O)--, nicotinoyl C₅ H₄ N--C(O)--, and the like.

As used herein, the term "C₁ -C₄ alkyl" refers to a saturated straightor branched chain hydrocarbyl radical of one to four carbon atoms andincludes methyl, ethyl, propyl, isopropyl, tertiary butyl, and the like.

As used herein, the term "pharmaceutically-acceptable salts" refers toacid addition salts of the compounds of formula (1) wherein the toxicityof the compound is not increased compared to the non-salt.Representative examples of pharmaceutically-acceptable salts, which aremade by treating the compounds of formula (1) with the correspondingacids, are: hydrobromide, hydrochloride, sulfuric, phosphoric, nitric,formic acetic propionic, succinic, glycolic, lactic, malic, tartaric,citric ascorbic, α-ketoglutaric, glutamic, aspartic, maleic,hydroxymaleic, pyruvic, phenylacetic, benzoic, para-aminobenzoic,anthranilic, para-hydroxybenzoic, salicylic, para-aminosalicylic,methanesulfonic, ethanesulfonic, hydroxyethanesulfonic,ethylenesulfonic, halobenzenesulfonic, toluenesulfonic,naphthalenesulfonic and sulfanilic acids. The hydrochloride is preferredas the pharmaceutically-acceptable salt of compounds of formula (1).

It is understood that the substituents on the cyclopentanyl ring of thecompounds of formula (1) have a TRANS configuration relative to thebicyclic substituent. It is further understood that the compounds offormula (1) may exist in stereoisomeric configurations. The compounds offormula (1) encompass and include both the individual stereoisomers andracemic mixtures.

A general synthetic procedure for preparing compounds of formula (1)wherein Y₉ is nitrogen is set forth in Scheme A. ##STR3##

The 1-hydroxy of cis-3-acetoxycyclopentan-1-ol is derivatized with asuitable leaving group (L) in step a of Scheme A. The particular leavinggroup can be one of many which are well known and appreciated in theart. Representative examples of suitable leaving groups are brosyl,tosy, mesylate. The preferred leaving group for step a is the mesylate.

In step b the leaving group of the cyclopentane derivative formed instep a is displaced with the desired nucleoside base, forming thetrans-carbocyclic nucleoside analog. The preferred base for step b isadenine. When the 3-acetoxy analog is desired, the product of step b maybe isolated or converted to the appropriate salt using procedures wellknown and appreciated in the art.

In step c the acetoxy group may be hydrolyzed with a base such apotassium carbonate to an alcohol according to procedures which are wellknown and appreciated in the art. When the 3-hydroxy analog ispreferred, the product of this reaction may be isolated or converted tothe appropriate salt using procedures well known and appreciated in theart.

In step d the 3-hydroxyl group may be converted to other alkyl acyl oraryl acyl (R') analogs by techniques which are well known andappreciated in the art. For example if the benzoyl derivative isdesired, the 3-hydroxy carbocyclic nucleoside can be reacted withbenzoyl chloride in the presence of base to form the 3-benzoyl analogue.

The following example presents a typical synthesis as described byScheme A. This example is understood to be illustrative only and is notintended to limit the scope of the invention in any way. The followingterms have the indicated meaning: "g" refers to grams; "mmol" refers tomillimoles; ml refers to milliters; "DMF" refers to dimethylformamide;"°C" refers to degrees Celsius; "mg" refers to milligrams; "N" refers tonormality; "pH" refers to the negative log of the hydronium ion.

EXAMPLE 1 (1R,3R)-Trans-1(9-Adenyl)Cyclopentan-3-Ol Hydrochloride

Step a: (1S,3R)-Cis-1-Methanesulfonyloxy-3-acetoxycyclopentane

Add triethylamine dropwise (1.21 g, 12.0 mmol) to a stirring solution of(1S,3R)-cis-3-acetoxycyclopentan-1-ol (1.44 g, 10.0 mmol) andmethanesulfonyl chloride (1.29 g, 11.0 mmol) in 20 ml of methylenechloride at 0° C. Remove the ice bath after the addition is complete.Stir the solution for 20 minutes at room temperature, then, extract thesolution with water (30 ml) and brine (30 ml). Dry over sodium sulfateand concentrate the solution to give a yellow oil; 2.1 g of product (94%yield). Use this product immediately in the next reaction withoutfurther purification. ¹ H NMR (CDCL₃,TMS); 5.09 (m,2H), 2.98 (s,3H),2.4,1.9 (m,9H).

Step b: (1R,3R)-Trans-1-(9-Adenyl)-3-acetoxycyclopentane

To a stirring suspension of adenine (4.1 g, 30.0 mmol) in DMF (50 ml),add sodium hydride (60%, 1.0 g, 30.0 mmol). Heat the mixture at 55° C.for two hours. Add a solution of(1S,3R)-cis-1-methanesulfonyloxy-3-acetoxycyclopentane (2.0 g, 9.1 mmol)in 20 ml of DMF to the solution and allow to stir for 24 to 48 hours at55° C. Filter the solution then evaporate the DMF. Take the residue upin 100 ml of methylene chloride. Extract with water (2×200 ml) and brine(20 ml). Dry the solution with sodium sulfate and concentrate todryness. Take up the residue in methylene chloride then apply to a 40 gsilica gel column. Elute the product with 9:1 methylenechloride/ethanol. Collect the fraction containing the product andconcentrate to dryness; 1.32 g of product (56% yield). UV(MEOH; 261.5nm); α!₃₆₅ =-29.40 (c 1.7 mg./ml, MeOH); ¹ H-NMR(CDCL3, TMS)=8.35(s,1H), 7.82 (s,1H), 5.41 (m,1H), 5.09 (m, 1H), 2.55-1.8 (m,9H).

Step c: (1R,3R)-Trans-1-(9-Adenyl)-3-hydroxycyclopentane.

Add (1R,3R)-trans-1(9-adenyl)-3-acetoxycyclopentane (600 mg. 2.26 mmol.)and potassium carbonate (500 mg, 3.6 mmol.) to a solution of 25 ml ofmethanol and 5 ml of water. Stir the mixture at room temperature for 20minutes. Remove the solid potassium carbonate by filtration andconcentrate the filtrate to dryness. Take the residue up in ethanol(with 10% methanol), then allow to stand at room temperature for 30minutes and remove the precipitate which forms by filtration. Adjust thepH of the filtrate to pH 3 with 6N HCL and concentrate to dryness.Redissolve the material in water and lypholyze to a white powder; (540mg, 93% yield). UV (MeOH; 261 nm); α!₃₆₅ =-40° (c 0.6 mg/ml, MeOH); ¹ HNMR (DMSO-d6, TMS) 8.20 (s,1H), 8.17 (s,1H), 5.11 (m,1H), 4.44 (m,1H),2.4-2.1 (m,4H), 2.0 (m,1H), 1.7 (m,1H).

In general, where it is desired to synthesize the corresponding (1S,3S)enantiomer of the compounds of formula (1), procedures similar to thosedescribed above may be followed using the appropriate startingmaterials. The following example presents a typical synthesis asdescribed by Scheme A. This example is understood to be illustrativeonly and is not intended to limit the scope of the invention in any way.

EXAMPLE 2 (1S,3S)-Trans-1(9-Adenyl)Cyclopentan-3-Ol Hydrochloride

Step a: (1R,3S)-Cis-1-Methanesulfonyloxy-3-acetoxycyclopentane

Add triethylamine dropwise (1.21 g, 12.0 mmol) to a stirring solution of(1R,3S)-cis-3-acetoxycyclopentan-1-ol (1.44 g, 10.0 mmol) andmethanesulfonyl chloride (1.29 g, 11.0 mmol) in 20 ml of methylenechloride at 0° C. Remove the ice bath after the addition is complete.Stir the solution for 20 minutes at room temperature, then, extract thesolution with water (30 ml) and brine (30 ml). Dry over sodium sulfateand concentrate the solution to give a yellow oil; 2.1 g of product (94%yield). Use this product immediately in the next reaction withoutfurther purification. ¹ H NMR (CDCL₃,TMS); 5.09 (m,2H), 2.98 (s,3H),2.4,1.9 (m,9H).

Step b: (1S,3S)-Trans-1-(9-Adenyl)-3-acetoxycyclopentane

To a stirring suspension of adenine (4.1 g, 30.0 mmol) in DMF (50 ml),add sodium hydride (60%, 1.0 g, 30.0 mmol). Heat the mixture at 55° C.for two hours. Add a solution of(1R,3S)-cis-1-methanesulfonyloxy-3-acetoxycyclopentane (2.0 g, 9.1 mmol)in 20 ml of DMF to the solution and allow to stir for 24 to 48 hours at55° C. Filter the solution then evaporate the DMF. Take the residue upin 100 ml of methylene chloride. Extract with water (2×200 ml) and brine(20 ml). Dry the solution with sodium sulfate and concentrate todryness. Take up the residue in methylene chloride then apply to a 40 gsilica gel column. Elute the product with 9:1 methylenechloride/ethanol. Collect the fraction containing the product andconcentrate to dryness; 1.2 g of product (46% yield). UV(MEOH; 261.5nm); α!₃₆₅ =+29.4 (c 1.7 mg./ml,MeOH); ¹ H-NMR (CDCL3, TMS)=8.34 (s,1H),7.82 (s,1H), 5.41 (m, 1H), 5.09 (p,1H), 2.5-1.8 (m,9H).

Step c: (1S,3S)-Trans-1-(9-Adenyl)-3-hydroxycyclopentane.

Add (1S,3S)-trans-1(9-adenyl)-3-acetoxycyclopentane (1.2 g 4.6 mmol.)and potassium carbonate (1.0 g, 7.2 mmol.) to a solution of 25 ml ofmethanol and 5 ml of water. Stir the mixture at room temperature for 20minutes. Remove the solid potassium carbonate by filtration andconcentrate the filtrate to dryness. Take the residue up in ethanol(with 10% methanol), then allow to stand at room temperature for 30minutes and remove the precipitate which forms by filtration andconcentrate to dryness. Take up the residue in methylene chloride, thenapply to a 75 g silica gel column. Elute the product with 9:1 methylenechloride/ethanol. Collect the fraction containing the product andconcentrate to dryness. Add H₂ O and adjust the pH to 3 with 6N HCL andconcentrate to dryness. Redissolve the material in water and lypholyzeto a white powder; (900 mg, 76% yield). UV (MeOH; 261 nm); α!₃₆₅ =+40°(c 0.6 mg/ml, MeOH); ¹ H NMR (DMSO-d6, TMS) 8.20 (s,1H), 8.17 (s,1H),5.11 (p,1H), 4.44 (m,1H), 2.4-2.1 (m,4H), 2.0 (m,1H), 1.7 (m,1H).

EXAMPLE 3 (1R,3R)-Trans-1- 9-(2,6-Diamino)Purine!Cyclopentan-3-Ol

Step b: (1R,3R)-Trans-1- 9-(2,6-diamino)purine!-3-acetoxycyclopentane

To a stirring suspension of 2,6-diaminopurine sulfate (15.96 g, 60.0mmol) in 150 mL of DMF is added sodium hydride (60%, 5.79 g, 180.0mmol), and the moisture is then heated at 55° C. for two hours. Asolution of (1S,3R)-cis-1-methanesulfonyloxy-3-acetoxy-cyclopentane(4.44 g, 20.0 mmol) in 50 mL DMF is added to the solution and allowed tostir for 48 hours at 60° C. The DMF is then removed and the residue istaken up in 100 mL of methylene chloride and extracted with water andbrine. The solution if dried with sodium sulfate, then concentrated todryness, and the residue is taken up in methylene chloride and appliedto a silica gel column and the product is eluted with 9:1 methylenechloride/ethanol. The fraction containing the product is collected andconcentrated to dryness to give 2.3 g of product (42% yield). α!₅₈₉=+9.1° (c 0.002, MeoH); ¹ H-NMR (CDCl₃, TMS) 7.88 (s, 1H), 7.74 (s, 2H,exD₂ O), 5.85 (s, 2H, exD₂ O), 5.31 (m, 1H), 4.89 (p, 1H), 2.5-1.8 (m,9H).

Step c: (1R,3R)-trans-1- 9-(2,6-diamino)purine!cyclopentan-3-ol

The (1R,3R)-trans-1- 9-(2,6-diamino)purine!-3-acetoxycyclopentane (1.8g, 6.5 mmol) and potassium carbonate (2.6 g, 1.9 mmol) is added to 250mL of methanol and 5 mL of water, and solid potassium carbonate isremoved by filtration, and the filtrate is concentrated to dryness. Thesolid is purified on silica gel using methylene chloride/methanol (4:1)to give 1.3 g of product (86% yield). UV (EtOH; 257 nm and 283 nm);α!₃₆₅ =-16.7° (c 0.002, MeoH); ¹ H-NMR (DMSO-d₆, TMS) 7.79 (s, 1H), 6.56(s, 2H, exD₂ O), 5.76 (s, 2H, exD₂ O), 4.86 (p, 1H), 4.7 (br. s, 1H,exD₂ O), 4.34 (m, 1H), 2.3-1.8 (m, 5H), 1.56 (m, 1H).

The following compounds can be prepared by procedures analogous to thosedescribed above for Example 1 using readily available startingmaterials. The stereo configuration may be (1R,3R) or (1S,3S) or aracemic mixture of these configurations:

Trans-1- 9-(3-deazaadenyl)!-3-hydroxycyclopentane hydrochloride

Trans-1- 9-(7-deazaadenyl)!-3-hydroxycyclopentane hydrochloride

Trans-1- 9-purinyl!-3-hydroxycyclopentane hydrochloride

Trans-1- 9-(8-azaadenyl)!-3-hydroxycyclopentane hydrochloride

Trans-1- 9-(2-aminopurinyl)!-3-hydroxycyclopentane hydrochloride

Trans-1- 9-(2-amino-6-chloropurinyl)!-3-hydroxycyclopentanehydrochloride.

Trans-1- 9-(6-chloropurinyl)!-3-hydroxycyclopentane hydrochloride.

The starting materials for the synthetic scheme described above,including (1S,3R)-Cis-3-acetoxycyclopentan-1-ol, adenine,7-deazaadenine, purine, 8-azaadenine, 2-aminopurine, 2,6-diaminopurineand 2-amino-6-chloropurine, are readily available or can be madeaccording to conventional procedures and techniques well known andappreciated in the art.

The stereochemistry of the final product is controlled by the selectionof a starting material with the appropriate configuration.

A general synthesis procedure for preparing compounds of formula (1)where Y₈ and Y₉ are each a CH group is presented in Scheme B. ##STR4##

In step a, the cyclopentane derivative (7) is reacted with the sodiumanion of methyl methylsulfinylmethyl sulfide to yield the corresponding1,3-substituted derivative (8).

In step b, the sodium anion of (8) is reacted with the appropriatepyrimidine or pyridine derivative, such as5-amino-4,6-dichloropyrimidine, followed by hydrolysis to give thecorresponding ketone derivative (9).

In step c, the ketone derivative (9) is converted to the correspondingenol ether (10) by reacting (9) with the appropriate Wittig reagent,such as φ₃ P═CH₂ OCH₃ methoxymethyl triphenylphosphylidine chloride!, inthe presence of n-butyllithium.

In step d, the enolate (10) is cyclized in the presence of acid, such asHCl, and the 3-hydroxy blocking group is removed according to standardtechniques well known and appreciated in the art, to give the6-substituted carbocyclic nucleoside analog (11).

In step e, the 6-substituted carbocyclic nucleoside analog (11) ismodified to form the alkyl acylated or arylacyl derivative as describedin Scheme A, step e, to yield the 9-substituted nucleoside derivative(1b). Where the 9-substituted carbocyclic nucleoside analog (11) bears achlorine in the 6-position, the 6-chloro derivative can be converted tothe 6-amino or 6-hydrogen derivative according to standard techniqueswell known and appreciated in the art.

The following example presents a typical synthesis as described byScheme B. This example is understood to be illustrative only and is notintended to limit the scope of the invention in any way.

EXAMPLE 4 (1R,3R)-Trans-1- 9-(9-deazaadenyl)!3-hydroxycyclopentanehydrochloride

Step a: (1R,3R)-Trans-3-t-butyldimethylsilylox-1-methyl(1-methylsulfinyl-1-methylsulfide)! cyclopentane

To a stirring solution of methylsulfinylmethyl sulfide (1.2 equivalents)in THF at 0° C. add n-butyl lithium (1.2 equivalents) and allow to stirfor 15 minutes. Over a 15 minute period, add dropwise a solution of(1S,3R)-Cis-1-methanesulfonyloxy-3-t-butyldimethylsilyloxy cyclopentane(1 equivalent) in THF and allow to stir for several hours at 0° C. to25° C. Dilute the reaction with water and extract with ethyl acetate ormethylene chloride. Wash the organic layer with water, brine, and dryover sodium sulfate. Concentrate the solution to dryness to yield thetitle compound as a crude product.

Step b: (1R,3R)-Trans-3-t-butyldimethylsilyloxy-1- carbonyl(4-5-amino-6-chloropyrimidine!)! cyclopentane

To a stirring solution of (1R,3R)-trans-3-t-butyldimethylsilyloxy-1-methyl(1-methylsulfinyl-1-methylsulfide)! cyclopentane (1 equivalent) inTHF at 0° C. add n-butyllithium and continue stirring for 15 minutes.Over a 15 minute period, add dropwise a solution of5-amino-4,6-dichloropyrimidine (1.1 equivalents) in THF and stir thereaction mixture for 24 hours at room temperature. Dilute the reactionwith water and extract with ethyl acetate or methylene chloride. Washthe organic layer with water, brine, and dry over sodium sulfate.Concentrate the solution to dryness to yield the title compound as acrude product. Purify the title compound using a silica gel columneluting with ethyl acetate/hexane.

Step c: (1R,3R)-Trans-3-t-butyldimethylsilyloxy-1- ethylene-1-(4-5-amino-6-chloropyrimidine!)-2-methoxy!cyclopentane

To a stirring suspension of methoxymethyl triphenylphosphylidinechloride (1.2 equivalents) in THF at 0° C. add n-butyllithium (1.2equivalents) followed by stirring for 1 hour. Over a 15 minute period,add (1R,3R)-trans-3-t-butyldimethylsilyloxy-1- carbonyl(4-5-amino-6-chloropyrimidine!)!cyclopentane (1 equivalent) in THF and stirovernight at 0° C. Concentrate the reaction mixture to dryness anddissolve the residue in diethyl ether. Cool to 0° C. for 1 hour andremove the precipitate (lithium chloride and triphenylphosphineoxide) byfiltration. Concentrate the filtrate to yield the title compound. Purifythe title compound using a silica gel column eluting with ethylacetate/hexane.

Step d: (1R,3R)-trans-1- 9-(9-deazaadenyl)!-3-hydroxy cyclopentaneHydrochloride

Dissolve (1R,3R)-trans-3-t-butyldimethylsilyloxy-1- ethylene-1-(4-5-amino-6-chloropyrimidine!)-2-methoxy!-cyclopentane in aqueous methanoland a sufficient amount of 6N HCl and stir at room temperature for 4hours. Neutralize the product with ammonium hydroxide and concentratethe reaction mixture to dryness to yield(1R,3R)-trans-3-t-butyldimethylsilyloxy-1-9-(6-chloro-9-deazapurinyl)!cyclopentane. Purify the product using asilica gel column eluting with methylene chloride/ethanol. Enclose(1R,3R)-trans-3-t-butyldimethylsilyloxy-1-9-(6-chloro-9-deazapurinyl)!cyclopentane in a sealed container ofmethanol and anhydrous ammonia for 24 hours applying heat if necessary.Remove the solvent and apply the product to a Dowex 50W™ column elutingwith dilute ammonium hydroxide. Concentrate the eluant to dryness, takeup in water, make acidic with 6N HCl and stir for 4 hours. Concentratethe solution to dryness to yield the title compound.

A general synthetic procedure for preparing compounds of formula (1)wherein Y₉ is a CH group and Y₈ is a nitrogen is set forth in Scheme C.##STR5##

In step a, the ketone derivative (9), made as described in Scheme B, isconverted to the corresponding oxime derivative and then cyclized to thecorresponding 8-aza-9-deaza-6-substituted-nucleoside derivative byreacting the oxime with diethylazodicarboxylate (DEAD) andtriphenylphosphine. In addition, the 3-hydroxy blocking group of (9) isremoved according to standard techniques well known and appreciated inthe art.

In step b, the 8-aza-9-deaza-6-substituted-nucleoside derivative can beconverted to the corresponding 8-aza-9-deaza-6-substituted-nucleosidealkyl acyl or arylacyl derivative as described in Scheme A, step e.Where the 8-aza-9-deaza-6-substituted-carbocyclic-nucleoside derivative(1c) bears a chlorine in the 6-position, the 6-chloro derivative can beconverted to the 6-amino or 6-hydrogen derivative according to standardtechniques well known and appreciated in the art.

EXAMPLE 5 (1R,3R)-Trans-1- 9-(8-aza-9-deazaadenyl)!3-hydroxycyclopentanehydrochloride

Step a: (1R,3R)-trans-1- 9-(8-aza-9-deazaadenyl)!-3-hydroxy cyclopentaneHydrochloride

To a solution of (1R,3R)-trans-3-t-butyldimethylsilyloxy-1- carbonyl(4-5-amino-6-chloropyrimidine!)!-cyclopentane (1 equivalent) andhydroxylamine hydrochloride (1.2 equivalents) in dry methanol add asolution of sodium hydroxide (1.2 equivalents). After 2 hours add waterand collect and dry the solid thus formed (oxime intermediate). Dissolvethe oxime intermediate (1 equivalent) in methylene chloride followed byDEAD (1.2 equivalents) and triphenylphosphine (1.1 equivalents). Allowthe mixture to react for 2 hours to yield(1R,3R)-Cis-3-t-butyldimethylsilyloxy-1-(9-8-aza-6-chloro-9-deazapurinyl!) cyclopentane. Extract the reactionmixture with water and then brine. Dry the organic layer over sodiumsulfate, concentrate to dryness and add diethyl ether to precipitate outthe triphenylphosphine oxide. Remove the precipitate by filtration andpurify the product on a silica gel column eluting with ethylacetate/hexane.

Enclose (1R,3R)-trans-3-t-butyldimethylsilyloxy-1-(9-8-aza-6-chloro-9-deazapurinyl!)-cyclopentane in a sealed container ofmethanol and anhydrous ammonia for 24 hours applying heat if necessary.Remove the solvent and apply the product to a Dowex 50W™ column elutingwith dilute ammonium hydroxide. Concentrate the eluant to dryness, takeup in water, make acidic with 6N HCl and stir for 4 hours. Concentratethe solution to dryness to yield the title compound.

EXAMPLE 6 (1R,3R)-Trans-1- 9-(6-amino-2-cholopurinyl)!cyclopentan-3-olhydrochloride

To a stirred solution of triphenyl phosphate (790 mg, 3.00 mmol) in dryTHF (7 ml) at 0 C was added diethyl azodicarboxylate (530 mg, 3.00 mmol)dropwise over a period of 15 minutes under N₂. The resultingorange-colored solution was allowed to stir for another 45 minutes atroom temperature. The reaction mixture was then chilled to -78 C and asolution of 2.6-dichloropurine (285 mg, 1.50 mmol) and(1S,3R)-cis-3-acetoxyclyclopentan-1-ol (144 mg, 1.00 mmol) in dry THF (3ml) was added. The resulting solution was warmed to room temperature andstirred for 36 hours. The reaction mixture was concentrated nd theresidue was chromatographed on a silica gel column eluting with 2.5%methanol in methylene chloride to yield 515 mg of(1R,3R)-Trans-3-acetoxy-1- 9-(2,6-dicholopurinyl)! as a crude mixture.

A solution of (1R,3R)-Trans-3-acetoxy-1- 9-(2,6-dicholopurinyl)! (515mg, crude) in anhydrous ethanol (15 ml) in a Dieis-Alder tube waschilled to -78 C under N₂. A rapid stream of NH₃ gas was passed throughthis solution for 5 minutes. The reaction tube was then sealed an theresulting solution was allowed to warm to room temperature and stirredfor 15 hours at room temperature. The reaction mixture was concentratedand the residue was chromatographed on silic gel column eluting with 4%methaanol in methylene chloride to yield 300 mg reddish oil.

The reddish oil was taken up in methanol (5 ml). K₂ CO₃ (200 mg, 1.45mmol) was added and the resulting mixture was stirred for 5 hours. Thereaction mixture was concentrated and the residue was chromatographed ona silica gel column eluting with 6% methanol in methylene chloride toyield 130 mg of (1R,3R)-Trans-1-9-(6-amino-2-cholopurinyl)!cyclopentan-3-ol (51% overall yield) as awhite solid. (1R,3R)-Trans-1-9-(6-amino-2-cholopurinyl)!cyclopentan-3-ol was converted to amonohydrochloride salt: Optical Rotation D +9.828 (0.755 w/v %, MeOH);analysis for (C₁₀ H₁₃ Cl₂ N₅ O): C, 41.40; H, 4.48; N, 24.10; found C,41.75; H, 4.37; N, 23.79.

EXAMPLE 7 Alkyl Acyl and Aryl Acyl Derivatives

Alkyl acyl and aryl acyl derivatives may be made from any of the abovecompounds. For example, (1R,3R)-trans-1-(9-adenyl)-3-hydroxycylopentane(1 mmol) is dissolved in pyridine (10 ml) and cooled to 0-5 C. Acyl acidchloride (1.1 mmol) is added dropwise and the reaction is stirred for 12hours at room temperature. The reaction is diluted with CH₂ Cl₂ andextracted with water, brine and concentrated to dryness. The material ispurified on silica gel (20 g) eluting with 9:1 CH₂ Cl₂ /MeOH as asolvent system.

In general, where it is desired to synthesize the corresponding (1S,3S)enantiomer of the compounds of formula (1), procedures similar to thosedescribed above may be followed using the appropriate startingmaterials.

The present invention further provides a method of effectingimmunosuppression, and more specifically, a method of suppressingadaptive immunity, in a patient in need thereof comprising administeringto said patient an effective immunosuppressive amount of a compound offormula (1).

As used herein, the term "patient" refers to a warm-blooded animal suchas a mammal which is suffering from a disease, such as an autoimmunedisease or "graft versus host" disease, or is in danger of rejection ofa transplanted allogeneic tissue or organ. It is understood that humans,mice and rats are included within the scope of the term "patient".

Administration of a compound of formula (1) to a patient results in animmunosuppressive effect in the patient. More specifically,administration of a compound of formula (1) to a patient results insuppression of adaptive immunity in the patient. In other words, bytreatment of a patient with a compound of formula (1), the adaptiveimmune response of the patient is inhibited or suppressed over thatpresent in the absence of treatment.

A patient is in need of treatment with an immunosuppressive agent, suchas a compound of formula (1), where the patient is suffering from anautoimmune disease, "graft versus host" disease or in order to preventrejection of transplanted allogeneic tissues or organs. The term"autoimmune disease" refers to those disease states and conditionswherein the immune response of the patient is directed against thepatient's own constituents resulting in an undesirable and oftenterribly debilitating condition.

Patients suffering from autoimmune diseases such as rheumatoidarthritis, insulin-dependent diabetes mellitus, certain hemolyticanemias, rheumatic fever, thyroiditis, septic shock syndrome,ulceractive colitis, myestheniagravis, glomerulonephritis, allergicencephalo-myelitis, continuing nerve and liver destruction whichsometimes follows viral hepatitis, multiple sclerosis and systemic lupuserythematosus are in need of treatment with an immunosuppressive agentsuch as a compound of formula (1). Rheumatoid arthritis,insulin-dependent diabetes mellitus and multiple sclerosis arecharacterized as being the result of a cell-mediated autoimmune responseand appear to be due to the action of T-cells. Myestheniagravis andsystemic lupus erythematosus are characterized as being the result of ahumoral autoimmune response. As such, treatment of patients sufferingfrom these diseases by administration of a compound of formula (1) willbe particularly effective in preventing further deterioration orworsening of the patient's condition. Treatment of a patient at an earlystage of an autoimmune disease, such as rheumatoid arthritis,insulin-dependent diabetes mellitus, multiple sclerosis,myestheniagravis or systemic lupus erythematosus, would be particularlyeffective in preventing further deterioration of the disease state intoa more serious condition. For example, insulin-dependent diabetesmellitus (IDDM) is an autoimmune disease which is believed to resultfrom the autoimmune response directed against the B-cells of the isletsof Langerhans which secrete insulin. Treatment of a patient sufferingfrom an early stage of IDDM prior to the complete destruction of theB-cells of the islets of Langerhans would be particularly useful inpreventing further progression of the disease since it would prevent orinhibit further destruction of remaining insulin-secreting μ-cells. Itis understood that treatment of a patient suffering from an early stageof other autoimmune diseases will also be particularly useful to preventor inhibit further natural progression of the disease state to moreserious stages.

Patients who have received or who are about to receive an allogeneictissue or organ transplant, such as an allogeneic kidney, liver, heart,skin, bone marrow, are also patients who are in need of prophylactictreatment with an immunosuppressive agent such as a compound of formula(1). An immunosuppressive agent will prevent the adaptiveimmune responseof the donee from rejecting the allogeneic tissue or organ of the donor.Likewise, patients suffering from "graft versus host" disease arepatients who are in need of treatment with an immunosuppressive agentsuch as a compound of formula (1). An immunosuppressive agent willprevent the adaptive immune response of the transplanted tissue or organfrom rejecting the allogeneic tissue or organ of the donee.

Based on standard clinical and laboratory tests and procedures, anattending diagnostician, as a person skilled in the art, can readilyidentify those patients who are in need of treatment with animmunosuppressive agent such as a compound of formula (1).

An effective immunosuppressive amount of a compound of formula (1) isthat amount which is effective, upon single or multiple doseadministration to a patient, in providing an immunosuppressive effector, more particularly, a suppression of adaptive immune response. Animmunosuppressive effect refers to the slowing, interrupting, inhibitingor preventing the further expression of the adaptive immune response.

An effective immunosuppressive amount of a compound of formula (1) canbe readily determined by the attending diagnostician, as one skilled inthe art, by the use of known techniques and by observing resultsobtained under analogous circumstances. In determining the effectiveamount or dose, a number of factors are considered by the attendingdiagnostician, including, but not limited to: the species of mammal; itssize, age, and general health; the specific disease involved; the degreeof or involvement or the severity of the disease; the response of theindividual patient; the particular compound administered; the mode ofadministration; the bioavailability characteristics of the preparationadministered; the dose regimen selected; the use of concomitantmedication; and other relevant circumstances.

An effective immunosuppressive amount of a compound of formula (1) isexpected to vary from about 0.1 milligram per kilogram of body weightper day (mg/kg/day) to about 500 mg/kg/day. Preferred amounts areexpected to vary from about 1 to about 50 mg/kg/day.

In effecting treatment of a patient, a compound of formula (1) can beadministered in any form or mode which makes the compound bioavailablein effective amounts, including oral and parenteral routes. For example,compounds of formula (1) can be administered orally, subcutaneously,intramuscularly, intravenously, transdermally, intranasally, rectally,and the like. Oral administration is generally preferred. One skilled inthe art of preparing formulations can readily select the proper form andmode of administration depending upon the particular characteristics ofthe compound selected the disease state to be treated, the stage of thedisease, and other relevant circumstances.

The compounds can be administered alone or in the form of apharmaceutical composition in combination with pharmaceuticallyacceptable carriers or excipients, the proportion and nature of whichare determined by the solubility and chemical properties of the compoundselected, the chosen route of administration, and standardpharmaceutical practice. The compounds of the invention, while effectivethemselves, may be formulated and administered in the form of theirpharmaceutically acceptable acid addition salts for purposes ofstability, convenience of crystallization, increased solubility and thelike.

In another embodiment, the present invention provides compositionscomprising a compound of formula (1) in admixture or otherwise inassociation with one or more inert carriers. These compositions areuseful, for example, as assay standards, as convenient means of makingbulk shipments, or as pharmaceutical compositions. An assayable amountof a compound of formula (1) is an amount which is readily measurable bystandard assay procedures and techniques as are well known andappreciated by those skilled in the art. Assayable amounts of a compoundof formula (1) will generally vary from about 0.001% to about 75% of thecomposition by weight. Inert carriers can be any material which does notdegrade or otherwise covalently react with a compound of formula (1).Examples of suitable inert carriers are water; aqueous buffers, such asthose which are generally useful in High Performance LiquidChromatography (HPLC) analysis; organic solvents, such as acetonitrile,ethyl acetate, hexane and the like; and pharmaceutically acceptablecarriers or excipients.

More particularly, the present invention provides pharmaceuticalcompositions comprising an effective immunosuppressive amount of acompound of formula (1) in admixture or otherwise in association withone or more pharmaceutically acceptable carriers or excipients.

The pharmaceutical compositions are prepared in a manner well known inthe pharmaceutical art. The carrier or excipient may be a solid,semi-solid, or liquid material which can serve as a vehicle or mediumfor the active ingredient. Suitable carriers or excipients are wellknown in the art. The pharmaceutical composition may be adapted for oralor parenteral use, including topical use, and may be administered to thepatient in the form of tablets, capsules, suppositories, solution,suspensions, or the like.

The compounds of the present invention may be administered orally, forexample, with an inert diluent or with an edible carrier. They may beenclosed in gelatin capsules or compressed into tablets. For the purposeof oral therapeutic administration, the compounds may be incorporatedwith excipients and used in the form of tablets, troches, capsules,elixirs, suspensions, syrups, wafers, chewing gums and the like. Thesepreparations should contain at least 4% of the compound of theinvention, the active ingredient, but may be varied depending upon theparticular form and may conveniently be between 4% to about 70% of theweight of the unit. The amount of the compound present in compositionsis such that a suitable dosage will be obtained. Preferred compositionsand preparations according to the present invention are prepared so thatan oral dosage unit form contains between 5.0-300 milligrams of acompound of the invention.

The tablets, pills, capsules, troches and the like may also contain oneor more of the following adjuvants: binders such as microcrystallinecellulose, gum tragacanth or gelatin; excipients such as starch orlactose, disintegrating agents such as alginic acid, Primogel, cornstarch and the like; lubricants such as magnesium stearate or Sterotex;glidants such as colloidal silicon dioxide; and sweetening agents suchas sucrose or saccharin may be added or a flavoring agent such aspeppermint, methyl salicylate or orange flavoring. When the dosage unitform is a capsule, it may contain, in addition to materials of the abovetype, a liquid carrier such as polyethylene glycol or a fatty oil. Otherdosage unit forms may contain other various materials which modify thephysical form of the dosage unit, for example, as coatings. Thus,tablets or pills may be coated with sugar, shellac, or other entericcoating agents. A syrup may contain, in addition to the presentcompounds, sucrose as a sweetening agent and certain preservatives, dyesand colorings and flavors. Materials used in preparing these variouscompositions should be pharmaceutically pure and non-toxic in theamounts used.

For the purpose of parenteral therapeutic administration, includingtopical administration, the compounds of the present invention may beincorporated into a solution or suspension. These preparations shouldcontain at least 0.1% of a compound of the invention, but may be variedto be between 0.1 and about 50% of the weight thereof. The amount of theinventive compound present in such compositions is such that a suitabledosage will be obtained. Preferred compositions and preparationsaccording to the present invention are prepared so that a parenteraldosage unit contains between 5.0 to 100 milligrams of the compound ofthe invention.

The solutions or suspensions may also include the one or more of thefollowing adjuvants: sterile diluents such as water for injection,saline solution, fixed oils, polyethylene glycols, glycerine, propyleneglycol or other synthetic solvents; antibacterial agents such as benzylalcohol or methyl paraben; antioxidants such as ascorbic acid or sodiumbisulfite; chelating agents such as ethylene diaminetetraacetic acid;buffers such as acetates, citrates or phosphates and agents for theadjustment of tonicity such as sodium chloride or dextrose. Theparenteral preparation can be enclosed in ampules, disposable syringesor multiple dose vials made of glass or plastic.

As with any group of structurally related compounds which possesses aparticular generic utility, certain groups and configurations arepreferred for compounds of formula (1) in their end-use application.Compounds of the formula (1) wherein Y₃ is nitrogen are generallypreferred. Compounds of the formula (1) wherein Y₅ is nitrogen aregenerally preferred. Compounds of the formula (1) wherein Y₇ is nitrogenare generally preferred. Compounds of the formula (1) wherein Y₈ is a CHgroup are generally preferred. Compounds of the formula (1) wherein Y₉is nitrogen are generally preferred. Furthermore, compounds of theformula (1) wherein Q is NH₂ and Z is hydrogen are generally preferred.Also preferred are compounds of the formula (1) wherein Q is NH₂ and Zis a halogen.

The following specific compounds of formula (1) are especiallypreferred:

(1R,3R)-Trans-1-(9-adenyl)-3-hydroxycyclopentane hydrochloride,

(1S,3S)-Trans-1-(9-adenyl)-3-hydroxycyclopentane hydrochloride, and

(1R,3R)-Trans-1 9-(6-amino-2-chloropurinyl)!cyclopentanol-3-olhydrochloride.

Also preferred are compounds of formula (1) where Q is NH₂, Z ishydrogen and R is C₁ to C₇ alkyl acyl, such as where R is methyl, ethyl,propyl, isopropyl, butyl, isobutyl, tert-butyl, sec-butyl, pentyl,isopentyl, neopentyl, and the like. One skilled in the art would knowhow to make these based on the teachings in Example 1, step b, whichexemplifies where R is methyl,(1R,3R)-trans-1-(9-adenyl)-3-acetoxycyclopentane and Example 7.

The following studies illustrate the utility of the compounds of formula(1). These studies are understood to be illustrative only and are notintended to limit the scope of the invention in any way. As used hereinthe following terms have the indicated meanings: "μM" refers tomicromolar concentration; "Units" refers to the internationally acceptedmeasurement of protein; "S.D." refers to standard deviation; "ηmol"refers to nanomoles; "ηg" refers to nanograms.

Regulation of MHC Class II Expression

Using the method of Edwards (J. of Cell Biochemistry 5E,155 (1991)), theability of a compound of formula (1) to reduce Major Histocompatibilitycomplex (MHC) class II antigen levels on macrophages (Mφ) obtained fromM. tuberculosis-treated rats may be measured. Cells obtained fromtreated rats are plated into tissue culture for a period of 4 hours topurify adherent cells, then treated with increasing levels of drug for aperiod of 18 hours. After this incubation period, cells are scraped fromthe dishes and stained using flow cytometry analysis with variousmonoclonal antibodies such as OX-6 a monoclonal antibody specific forMHC class II antigens and OX-42 a monoclonal antibody specific for ratmacrophages. Data indicate (1R,3R)-Trans-1(9-Adenyl)cyclopentan-3-0lhydrochloride (10 uM) reduces the expression of MHC II antigenexpression on rat macrophages in vitro by nearly 33% (39% OX-6/OX-42double positive macrophages) compared to the positive control ratmacrophages obtained from Tuberculosis-treated rats (59% OX-6/OX42double positive macrophage cells).

Regulation of Antigen Presentation to Rat T-Cell Hybridoma

Using the method of Ku (Cellular Immunology 130, (1990)), and a Lewis(LEW/N) rat T-cell hybridoma reactive with the protein methylated bovineserum albumin (mBSA), the ability of a compound of formula (1) toregulate Mφ antigen presentation in vitro may be measured. Peritonealmacrophages obtained from LEW/N rats are plated into tissue culture andtreated with 100 ug of mBSA and drug. A control is prepared similarly.After a period of 18 hours the cells are washed and incubated with theT-cell hybridoma for an additional 12 hours. Supernatants from thesecultures are obtained and measured for content of Interleukin-2, aT-cell derived lymphokine which is produced by activated T-cells. Dataindicate (1R,3R)-Trans-1(9-Adenyl)cyclopentan-3-Ol hydrochlorideinhibits T-cell activation. Rat macrophage antigen presentation and thesubsequent production of Interleukin-2 are inhibited when drug isadministered over a concentration range from 0.1 to 100 uM asillustrated in the following table.

    ______________________________________                                        In Vitro Concentration                                                                         % Inhibition                                                 ______________________________________                                         0.1 uM          7.6                                                           1.0 uM          30.9                                                          10.0 uM         48.7                                                         100.0 uM         55.3                                                         ______________________________________                                    

Regulation of Endotoxin Lethality

Using the method of Silverstein, (J. Exp. Med. 173, 357 (1991)) a mouseendotoxin lethality model may be used to determine if a compound offormula (1) has the ability to inhibit endotoxin-induced septic shockwhich is dependent on the production of Tumor Necrosis Factor-α (TNF-α).CF1 mice pretreated at time (t)=-1 hr with drug are challenged with 18mg of D-glactoseamine and 50 ng of LPS, then observed for death over an8-72 hour period. Data indicate(1R,3R)-Trans-1(9-Adenyl)cyclopentan-3-Ol hydrochloride (100 mg/kg i.p.)protects against endotoxin lethality.

Inhibition of tumor Necrosis Factor Alpha

Peripheral blood mononuclear cells (PBMC) are isolated from venous bloodcollected from healthy volunteers in sodium citrate (5 ml of 3.6% sodiumcitrate for 45 ml of blood) by density gradient centrifugation of 5minutes at 1500 rpm. The PBMC are resuspended in about 10 ml ofRPMI-1640 with antibiotics. Approximately 2×10⁶ cells of PBMC are addedto tissue culture plates, incubated for 45-60 minutes at 37 C with 5%CO₂, aspirated, and washed twice by adding about 0.5 ml fresh RPMI-1640with 10% non-mitogenic FBS (RPMI complete) and shaking for 15 to 30seconds. 1.0 ml RPMI-1640 is added per well to the remaining adherentcells, which are pretreated with test compound solution about 15 minutesprior to endotoxin stimulation (1 μg/ml lipopolysaccharide from E. colior solvent concentrations equal to those of test compounds.

Cultures are incubated for 18 hours t 37 C in 5% CO2. Supernatants aretested from TNF-a using a commercial ELISA kit (Cistron, Pine Brook,N.J.). The IC₅₀ is determined using SOFTmax software program.

The IC₅₀ values for (±)-Trans-1-(9-adenyl)-2-hydroxycyclopentane(described in Lin U.S. Pat. No. 3,917,837) is 22.2 μM; for(1R,3R)-Trans-1-(9-Adenyl)cyclopentan-3-Ol hydrochloride, 9 μM; and for(1R,3R)-Trans-1- 9-(6-amino-2-cholopurinyl)!cyclopentan-3-olhydrochloride, 4.1 μM.

What is claimed is:
 1. A compound of the formula ##STR6## wherein thesubstituent in the 3-position on the cyclopentanyl ring is in the TRANSconfiguration relative to the bicyclic substituent,Y₃, Y₅ and Y₉ areeach nitrogen and Y₇ and Y₈ are a CH group, R is a C₁ -C₇ alkyl acyl oraryl acyl, Q is NH₂, halogen or hydrogen, and Z is hydrogen, halogen, orNH₂ ;or a pharmaceutically-acceptable salt thereof.
 2. A compound ofclaim 1 wherein R is a C₁ -C₇ alkyl acyl.
 3. A compound of claim 2wherein R is methyl acyl.
 4. A compound of claim 2 wherein R is ethylacyl.
 5. A compound of claim 2 wherein Q is NH₂.
 6. A compound of claim5 wherein Z is hydrogen.
 7. A compound of claim 2 wherein Q is hydrogen.8. A compound of claim 5 wherein Z is NH₂.
 9. A compound of claim 1wherein R is an aryl acyl.
 10. A compound of claim 9 wherein Q is NH₂.11. A compound of claim 10 wherein Z is hydrogen.
 12. A method ofeffecting immunosuppression in a patient in need thereof comprisingadministering to said patient a compound of claim
 1. 13. A method ofsuppressing adaptive immunity in a patient in need thereof comprisingadministering to said patient a compound of claim
 1. 14. A methodaccording to claim 13 wherein the patient is in need of treatment forallograft rejection.
 15. A method according to claim 13 wherein thepatient is in need of treatment for an autoimmune disease.
 16. A methodaccording to claim 15 wherein the autoimmune disease isinsulin-dependent diabetes mellitus.
 17. A method according to claim 15wherein the autoimmune disease is multiple sclerosis.
 18. A methodaccording to claim 15 wherein the autoimmune disease is rheumatoidarthritis.
 19. A method according to claim 15 wherein the autoimmunedisease is myesthenia gravis.
 20. A method according to claim 15 whereinthe autoimmune disease is systemic lupus erythematosus.
 21. Acomposition comprising a compound of claim 1 in admixture or otherwisein association with an inert carrier.
 22. A pharmaceutical compositioncomprising a compound of claim 1 in admixture or otherwise inassociation with one or more pharmaceutically acceptable carriers orexcipients.
 23. A method of regulating major histocompatibility complexclass II antigen levels by administering a compound of claim
 1. 24. Amethod of inhibiting tumor necrosis factor alpha levels by administeringa compound of claim 1.